Liquid crystal display devices have advantageous features, such as thin profile, light weight, and low power consumption, which allow their wide use in electronic apparatuses such as monitors, projectors, mobile phones, and personal digital assistants (PDAs). Such liquid crystal display devices include a transmissive type, a reflective type, and a transflective type (both reflective and transmissive). Transmissive liquid crystal display devices perform display by outwardly emitting light guided from a back side, for example, light from a backlight provided at a back side of a liquid crystal display panel, to the inside of the liquid crystal display panel. Reflective liquid crystal display devices perform display by reflecting light guided from a front side (screen side), such as ambient light and light from a front light, to the inside of the liquid crystal display panel. In contrast, transflective liquid crystal display devices perform transmissive display by using light from the back side in a relatively dark environment, such as an indoor environment, and perform reflective display by using light from the front side in a relatively bright environment, such as an outdoor environment. Thus, transflective liquid crystal display devices provide both the excellent visibility of reflective liquid crystal display devices in a bright environment and the excellent visibility of transmissive liquid crystal display devices in a dark environment.
With regard to transflective liquid crystal display devices, a liquid crystal display device has been disclosed which has the following structure for achieving a bright display with a wide viewing angle in both transmissive display and reflective display (see Patent Document 1, for example). That is, a liquid crystal layer is formed of liquid crystal with a negative dielectric anisotropy which is vertically aligned in an initial alignment state, and a pair of substrates respectively include electrodes for driving the liquid crystal formed on the side that faces the liquid crystal layer. Alignment regulating means that regulates the alignment of the liquid crystal is provided on the electrode on at least one of the substrates. The alignment regulating means includes a slit-shaped opening formed by opening a longitudinal hole in the electrode and/or a longitudinal protrusion formed on the electrode and is made of a dielectric material. A liquid-crystal-layer-thickness adjusting layer is formed between at least one of the pair of substrates and the liquid crystal layer. The liquid-crystal-layer-thickness adjusting layer is provided for setting the liquid crystal layer thickness in the transmissive display region to be greater than the liquid crystal layer thickness in the reflective display region. The liquid-crystal-layer-thickness adjusting layer has an inclined surface in the vicinity of a boundary between the transmissive display region and the reflective display region so that the layer thickness thereof varies continuously. The longitudinal direction of the opening and/or the protrusion and the longitudinal direction of the inclined surface of the liquid-crystal-layer-thickness adjusting layer are arranged in such a manner as to intersect each other in a plan view.
Thus, a so-called multi-gap structure in which a liquid-crystal-layer-thickness adjusting portion is provided in a cell has been proposed as a way of matching voltage-transmission luminance characteristics in the transmissive region with voltage-reflection luminance characteristics in the reflective region in a transflective liquid crystal display device.
In contrast, a liquid crystal display device has been disclosed which has the following structure, instead of the multi-gap structure, as an art for achieving voltage-reflection brightness characteristics (VR characteristics) which is less likely to cause tone reversal (see Patent Document 2, for example). That is, the liquid crystal display device includes a pair of substrates and a liquid crystal layer interposed between the pair of substrates. The liquid crystal display device is provided with a transmissive region and a reflective region. The reflective region includes a first section and a second section. The first section has a liquid crystal layer thickness greater than ½ of a liquid crystal layer thickness in the transmissive region but not greater than the liquid crystal layer thickness in the transmissive region. The second section has a liquid crystal layer thickness greater than the liquid crystal layer thickness in the transmissive region.
[Patent Document 1]
Japanese Kokai Publication No. 2004-279566 (JP-A 2004-279566)
[Patent Document 2]
WO 2008/129734